The goal of this proposal is to define the mechanisms involved in cell-to-cell transmission of HSV-1 during recurrent herpetic infection of the corneal epithelium. Recurrent herpetic infection of the cornea is a leading cause of blindness in humans. Understanding the mechanisms of cell-to-cell spread of virus in the cornea will be important in preventing this disease. The first specific aim is to identify factors in corneal epithelial cells that are utilized by the virus for cell-to-cell spread, such as proteins associated with cell junctions. The second aim is to target viral gene products involved cell-to-cell spread. The third aim focuses on identifying morphologic changes in infected corneal cells during cell-to-cell spread. The last aim is to develop and implement a culture system of viral infection that models the natural conditions of the eye to study the spread of virus from infected sensory neuron axons to corneal epithelial cells. Human corneal epithelial cells in culture will be inoculated with herpes simplex virus type. 1. Specific inhibitors of host proteins associated with cell junctions will be administered and their effects on cell-to-cell spread of virus determined. Mutant strains of herpes virus will be used to clarify specific viral gene products essential for viral spread. Morphological changes in the infected corneal cells will be monitored by light, confocal and electron microscopy. Finally, a novel culture system that models recurrent herpetic infection of cornea in vivo will be developed. Understanding how virus is spread cell-to-cell in the eye and the specific host and viral genes involved will be important for the development of effective treatments for recurrent corneal herpetic infection.